1. Technical Field
The present invention relates to a piping structure for supplying and discharging a fluid to a bladder provided in a tire vulcanizing machine.
2. Description of the Related Art
The tire vulcanizing machine is provided with upper and lower metal molds and a bladder which expands and contracts by supplying and discharging a fluid, and is structured such as to vulcanize a raw tire by pressing the bladder expanded by supplying the fluid to an inner surface of the raw tire which is set to an inner portion of the metal molds.
A main pipe is connected to an inner portion of the bladder, and a plurality of branch pipes (a steam supply pipe, a gas supply pipe, a shaving gas supply pipe, a gas recovery pipe, an exhaust pipe and the like) are connected to the main pipe via a plurality of valves.
As mentioned above, a plurality of branch pipes are connected to the main pipe via a plurality of valves, respectively.
Conventionally, the piping structure of each of the valves and each of the branch pipes with respect to the main pipe employs a two-way, three-way or four-way switch valve having a flange or an inside screw and an outside screw, and a valve unit is formed by assembling them in one position.
In the case that the valve unit is formed in the manner mentioned above, it is possible to intend an effective utilization of a space, however, in the conventional structure, when connecting each of the valves and the branch pipes to the main pipe, the structure is made such that the pipe is processed in an optional shape such as thread cutting the pipe and welding the flange, and the valve unit is finally formed by combining a lot of these pipes and valves.
Accordingly, in the conventional structure, the piping structure becomes complicated and constrained by a lot of pipes and flanges, so that there are problems that a lot of labor is required for keeping the pipes warm and a lot of labor is required for replacing the valves for maintenance. Further, in the case of securing an area for operating and maintaining the valves, there is a problem that the valve unit is enlarged in size.
Further, since a lot of pipes are complexly placed and the pipes are arranged approximately horizontally, there is also a problem that a drain is hard to beget out from the pipes due to an accumulation of the drain.
The present invention is made for the purpose of solving the conventional problems mentioned above, and an object of the present invention is to provide a piping structure in a tire vulcanizing machine which has a simple structure and an improved operability of a valve, can easily execute a maintenance work such as a valve replacement, and can form a compact valve unit having a reduced piping area.